Lubricants



LUBRICANTS Earl G. De Witt, Royal Oak, Mich., assignor to Ethyl Corporation, New York, N.Y., a corporation of Delaware N Drawing. Application May 10, 1957 Serial No. 658,250 I 4 Claims. (Cl. 25246.7)

' This invention relates to superior lubricant compositions and particularly to crankcase lubricants of enhanced performance characteristics.

In the operation of present-day automotive engines, particularly those of the high compression type, depositinduced engine problems, such as pre-ignition, autoignition and wild ping, are becoming severe. These problems result in a number of deleterious effects including rough engine operation, loss of engine power, decreased fuel economy and increased engine wear.

It has been found that crankcase lubricants contribute to the severity of deposit-induced engine problems. This results from the fact that under normal circumstances amounts of lubricating oil by-pass the piston rings and are thus introduced into the combustion chamber. As this happens the high temperatures encountered cause the lubricants to decompose with the consequent formation of gums, resins, or other relatively viscous decomposition products which act as binders for other products of combustion. Thus, there is an existingneed forimproved lubricant formulations, particularly from the standpoint of reducing their tendencies of promoting deposit-induced engine problems.

United States Patent 0 Among the objects of this invention is that of provid- I ing superior lubricant compositions which are not only devoid of wild ping-producing tendencies, but are capable of providing an unusually high reduction in the rate of this engine phenomenon. A particular object of this invention is to provide improved crankcase lubricants of superior performance characteristics. Other objects of this invention will become apparent from the ensuing description.

According to this invention, I provide improved lubricant compositions comprising lubricating oil and a tri- (jS-halopropyl)-thionophosphate containing from 1 to 4 sulfur atoms per molecule, the halogen having an atomic weight of at least 35. A preferred embodiment of this invention relates to improved crankcase lubricants containing a small but effective amount of a tri-(p-chloropropyl)-thionophosphate. This embodiment has been found particularly effective in reducing wild ping in spark ignition-type internal combustion engines. Another important advantage of this invention is that my lubricants are effective in reducing wild ping even where the amount of oil consumption in the engine is exceedingly low. This advantage is apparently tied in with the exceptionally high oil solubility and ideal volatility characteristics of the thionophosphate additives of this invention, especially in the case of the tri-(fi-chloropropyl)-thionophosphates. For example, tri-(B-chloropropyl)-thionophosphate was found to be over twenty-four times more soluble in min eral oil at room temperature (246 C.) than tri-(flchloroethyl -thionophosphate.

The hydrocarbon constituent of the compositions of this invention can be any hydrocarbon known in the art as a lubricant. Thus, it can be derived from various sources, such as vegetable, animal and mineral oil stocks. It is preferable, however, to use a mineral lubricating oil having Tice a viscosity corresponding to Society of Automotive.

Engineers classification SAE 5W through SAE 50. This classification of crankcase oil adopted in 1950 is as follows:

SAE viscosity No. 1

Viscosity range, Saybolt seconds SAE 5W 4,000 sec. at 0 F. max. (see Note C). SAE 10W 6,000 to 12,000 secs. at 0 F. (see Note A). SAE 20W-.. 12,000 to 48,000 secs. at 0 13". (see Note B). SAE 20 45 to 58 secs. at 210 F. SAE 3 58 to 70secs. at 210 F. SAE 40 70 to 85 secs. at 210 F. SAE 50 85 to 110 secs. at 210 F. NOTE. A.Minimum viscosity at 0 F. of the 10W grade can be 'waived provided the viscosity at 210- F. is not below 40 seconds Saybolt.

No'rn B.Minimum viscosity at 0 F. of the 20W grade can be waived provided the viscosity at 210 F. is not below 45 seconds Saybolt.

NOTE C.'lhe viscosity of oils. included in this classificatron for use in erankcases shall not be less than 39 seconds Saybolt at 210 F.

By selecting the hydrocarbon base stock according to the above classification, the maximum benefits obtainable from this invention are achieved.

The additives used in my lubricants are neutral B-halopropyl esters of thionophosphoric acids, the halogen atoms being chlorine, bromine and/or iodine. Thus, the addi-- chloropropyl) -monothiothionophosphate, trifi-bromoisopropyl) monothiothionophosphate, tri-(B-iodopropyD- monothiothionophosphate, 0,0-di-(fi-chloroisopropyl) -(B- bromopropyl) monothiothionophosphate, 0,0 di (18- chloropropyl) -(,6-iodopropyl) monothiothionophosphate, tri-(B-chloropropyl-dithiothionophosphate, tri-(B-bromopropyl) -dithiothionophosphate, tri-( fl-iodopropyl -dithiothionophosphate, S,S-di-(/8-chloropropyl) (fi-bromoisopropyl) -dithiothionophosphate, O,S-di-( fl-bromopropyl) (fl-iodopropyl) dithiothionophosphate, tri-(fl-chloroisopropyl) -trithiothionophosphate, tri- S-bromoisopropyl) trithiothionophosphate, tri-(fl-iodopropyl) trithiothionophosphate, difi-chloropropyl) -(;8bromopropyl) -trithiothionophosphate, andthe like.

The additives can be prepared by two. general methods. The first involves reacting at about 30 C. a thiophosphoryl tn'halide, such as thiophosphoryl trichloride with a ,B-halopropanol, fi-halopropyl thiol or a mixture of such compounds, the halogen atoms of the reactants having atomic weights of at least 35. In this method approximately three moles of alcohol or thiol are reacted with each mole of phosphorus reagent employed. Since three moles of hydrogen halide are produced, it is preferable to employ a halogen acceptor, such as an amine.

The second method for preparing the additives of this invention involves reacting propylene oxide or propylene sulfide at about 35 C. with a phosphorus trihalide whereby p a tri-(B-halopropyl)-phosphite is formed. Three moles of propylene oxide or propylene sulfide or mixtures thereof are consumed per each mole of phosphorus reagent present. The phosphite canthen be reacted with elemental sulfur to produce suitable oil additives. If desired, the propylene oxide or propylene sulfide or mix:

tures of the two can be reacted directly with such compounds as thiophosphoryl trichloride, thiophosphoryl Patented Nov.-10-, 1959- tribromide, thiophosphoryl triiodide or appropriate mixtures of these reagents.

The preferred additive of this invention is tri-(flchloropropyl)-thionophosphate. There are four isomers of this compound which give excellent results when used individually. Similarly, mixtures of two or more of these isomers are eminently suited for use according to this invention. The individual isomers are tri-(fl-chloro-npropyl)-thionophosphate having the formula (CH CHC1CH O) PS di (B chloro n -propyl) (5 chloroisopropyl)- thionophosphate having the formula (CH;CHC1CH2O):

P=S CH;-CHO

CHzCl di (B chloroisopropyl) ([3 chloro n propyl)- thionophosphate having the formula CHr-CHO CH;-CH-CHzO c1 and tri-( fi-chloroisopropyl -thionophosphate having the formula C Hz G1 These isomers and the various mixtures thereof are Water-white liquids having a characteristic odor and are stable in the presence of air and moisture even at elevated temperature. Their boiling points are in the range of 140-160" C./ l min. The specific gravity is approximately 1.3 at C. as compared with water at 4 C. They are relatively non-viscous, having a viscosity of approximately 30.1 centipoises at C. As pointed out above, they have the unexpected property of being extremely soluble in mineral oil hydrocarbons. This preferred additive contains approximately 31.5 percent carbon, 5.3 percent hydrogen, 30.8 percent chlorine, 14.0 percent oxygen, 9.1 percent phosphorus and 9.3 percent sulfur. Due to the high solubility of this preferred additive in mineral oil and to its high rate of solution therein, it can be blended readily into all types of mineral oils even at high concentration. Furthermore, the resulting mineral oil solutions remain completely homogeneous even at extremely low temperatures.

One method of preparing tri-(B-chloro-n-propyU- thionophosphate or tri-(fl-chloroisipropyl)-thionophosphate is to react respectively a material selected from the group consisting of 2-chloropropanol-1 and its alcoholate salts, or l-chloropropanol-Z and its alcoholate salts, with thiophosphoryl chloride. These reactions take place according to the following equations:

Where Y is selected from the group consisting of hydrogen and metallic ions. Where Y is a polyvalent metal, it is understood that suficient alcoholate radicals to satisfy its valence are present in the molecule. The metals most suitable for this use are the alkali and alkaline earth metals, particularly sodium, potassium, and calcium. When the reactions are carried out according to the above equations at moderate temperature, such as to 125 C. (when Y is hydrogen) and 0 to 50 C. (when Y is a metallic ion) reaction smoothly proceeds with the formation of these isomers in high yield and high purity. When the free chlorohydrin is used as the relit actant, the by-product is hydrogen chloride. It is important in obtaining high yields to remove the by-product hydrogen chloride as rapidly as it is formed in order to avoid attack by it on the organic molecule formed. This can be accomplished by removing hydrogen chloride from the reaction mixture by volatilization, leaving the particular isomer in substantially pure condition. One elegant method of volatilizing the hydrogen chloride is by blowing a stream of inert gas, such as nitrogen, through the reaction mixture as the reaction proceeds. Other methods of accomplishing this include operating the reaction under a slight vacuum and by use of a hydrogen chloride acceptor, such as an amine or ammonia, in the reaction medium.

In the embodiment in which an alcoholate salt of the chlorohydrin is used, care should be taken in preparing the alcoholate in order to avoid abstraction of chlorine from the chlorohydrin molecule. in the case of the alkali metal alcoholates this can be conveniently done by treating the chlorohydrin with an intirnate dispersion of alkali metal in a non-polar solvent, such as benzene or other inert hydrocarbon. When the particular isomer is prepared by reaction of an alcoholate salt with thiophosphoryl chloride, the by-product is then the halide of the alcoholate metal. This can be removed from my desired product by conventional means, such as filtration and centrifugation.

To prepare the other two isomers of tri-(B-chloropropyl)-thionophosphate, generally similar reaction conditions are used. Specifically, di-(B-chloro-n-propyl)-(B- chloroisopropyl)-thionophosphate is prepared by reacting one mole of thiophosphoryl chloride with two moles of a material selected from the group consisting of Z-chloropropanol-l and its alcoholate salts and with one mole of a material selected from the group consisting of l-chloropropanol-Z and its alcoholate salts. This can be done by reacting thiophosphoryl chloride first with two moles of 2-chloropropanol-1 or its alcoholate, followed by reaction of the intermediate product with one mole of l-chloropropanol-Z or its alcoholate, or it can be prepared by first reacting the thiophosphoryl chloride with one mole of l-chloropropanol-Z or its alcoholate, followed by reaction with two moles of 2-chloropro panel-1 or its alcoholate. This isomer can also be prepared by reacting thiophosphotyl chloride with one mole of 2-chloropropanol-l or its alcoholate, then one mole of 1-chloropropanol-2 or its alcoholate, and finally another mole of 2-chloropropanol-1 or its alcoholate. Another convenient method is the simultaneous reaction of two moles of 2-chloropropanol-1 or its alcoholate and one mole of 1-chloropropanol-2 or its alcoholate with one mole of thiophosphoryl chloride. By the same token, di (B chloroisopropyl) ([3 chloro n propyl)-thionophosphate is prepared by reacting one mole of thiophosphoryl chloride with two moles of a material selected from the group consisting of l-chloropropatrol-2 and its alcoholate salts and with one mole of a material selected from the group consisting of 2-chloropropanol-l and its alcoholate salts. This can be done by reacting thiophosphoryl chloride first with two moles of l-chloropropanol-Z or its alcoholate followed by reaction of the intermediate product with one mole of 2-chloropropanol-l or its alcoholate, or it can be prepared by first reacting the thiophosphoryl chloride with one mole of 2-chloropropanol-l or its alcoholate, followed by reaction with two rnoles of l-chloropropanol-Z or its alcoholate. This isomer can also be prepared by reacting thiophosphoryl chloride with one mole of l-chloropropanol-Z or its alcoholate, then one mole of 2-chloropropanol-l or its alcoholate, and finally another mole of l-chloropropanol-Z or its alcoholate. Another convenient method is the simultaneous reaction of two moles of 1-chloropropanol-2 or its alcoholate and one mole of 2-chloropropanol-l or its alcoholate with one mole of thiophosphoryl chloride.

The following examples more fully illustrate the preparation of the isomers of the preferred additive of this invention.

Example I To 168 parts of thiophosphoryl chloride contained in a stirred reaction vessel with liquid feed means and gas inlet and outlet means are added 285 parts of 2-chloropropanol-l over a period of 4 hours. The initial temper'ature is 50? C., and during the course of addition this is gradually raised to 125 C., at which temperature the reaction mixture is heated .for an additional 30 minutes after the addition of Z chIoroprOpanoI-I is complete. During the addition and subsequent heating periods a stream of nitrogen is constantly bubbled through the reaction mixture to entrain and remove the hydrogen chloride as it is formed, thus serving to purify the product, to prevent deterioration of the product and to hasten the reaction to completion. At the end of the reaction period the residual product, tri-(B-chloro-npropyl)-thionophosphate, a clear, mobile liquid, is of a purity sutiable for many uses. If desired, however, it can be further purified by vacuum distillation.

Example II The sodium alcoholate salt of 2-chloropropanol-1 is prepared by slowly adding 69 parts of metallic sodium finely dispersed in toluene to 285 parts of 2-chloropropanol-l in 500 parts of toluene. The temperature of addition of the sodium dispersion is kept in the range 0 to 20 C. As the reaction proceeds, the sodium alcoholate of 2-chloropropanol-l precipitates as a solid. A slurry of this alcoholate in the supernatent toluene is then added over a period of two hours to 168 parts of thiophosphorylchloride maintained at 20 C. At the end of this period the reaction mixture is cooled and sodium chloride removed by filtration. Toluene is then removed from the filtrate by distillation at 18 mm., leaving as the residue the desired product, tri(fi-chloro-npropyl)-thionophosphate. The product can be further purified by vacuum distillation at 1 mm. The yield of the desired product is nearly quantitative.

Example [II To 168 parts of thiophosphoryl chloride contained in a stirred reaction vessel with liquid feed means and gas inlet and outlet means are added 285 parts of 1-chloro propanol-2 over a period or" four hours. The initial temperature is 50 C., and during the course of addition this is gradually raised to 125 C., at which temperature the reaction mixture is heated for an additional 30 minutes after the addition of l-chloropropanol-Z is complete. During the addition and subsequent heating periods, a stream ofnitrogen is constantly bubbled through the reaction mixture to entrain the hydrogen chloride as it is formed, thus serving to purify the product to prevent deterioration of the product and to hasten the reaction to completion. At the end of the reaction period, the residual product, tri (,8 chloroisopropyl)- thionophosphate, a clear, mobile liquid, is of a purity suitable for many uses. If desired, however, it can be further purified by vacuum distillation.

Example I V The sodium alcoholate salt of l-chloropropanol-2 is prepared by slowly adding 69 parts of metallic sodium finely dispersed in toluene to 285 parts of 1-chloropropauol-2 in 500 parts of toluene. The temperature of addition of the sodium dispersion is kept in the range 0 to 20 C. As the reaction proceeds, the sodium alcoholate of l-chloropropanol-Z precipitates as a solid. A slurry of this alcoholate in the supcrnatent toluene is then added to 168 parts of thiophosphoryl chloride maintained at 20 C. for two hours. At the end of this period, the reaction mixture is cooled and sodium chloride removed by filtration. Toluene is then removed from the filtrate by distillation at 18 mm., and the product, tri-(p-chloroisopropyl)-thionophosphate, can be further. purified if desired by vacuum distillation at 1 mm. The yield of the desired product is nearly quantitative.

Example V The sodium alcoholate salt of 2-chloropropanol-1 is prepared by slowly adding 46 parts of metallic sodium as an intimate dispersion in toluene to 191 parts of 2- chloropropanol-l in 350 parts of toluene while the temperature of the reactor is maintained at 020 C. In the same manner the sodium alcoholate salt of l-c'hloro propanol-2 is separately prepared from 23 parts of metallic sodium and 96 parts "of l-chloropropanol-2. To 168 parts of thiophosphoryl chloride is added a slurry of the above prepared alcoholate of 2-chloropropanol-1 in the supernatent toluene at a reaction temperature of 20 C. The time of addition is two hours. At the end of this period, the reaction mixture-is cooled and sodium chloride removed by filtration. The residual product is then fractionated to yield di-(2-chloro-n-propyl)-chlorothionophosphate. This material is then reacted with the alcoholate of 1-chloropropanol-2 prepared above at 20 C. for an additional two hours. At the end of this time, the reaction mixture is again cooled and sodium chloride removed by filtration. Toluene is then removed from the filtrate by distillation at 18 mm., and the product, di- (p chloro n propyl) (fi chloroisopropyl) thionophosphate is further purified by fractionation under reduced pressure. The yield of desired product is nearly quantitative.

. Example VI The sodium alcoholate salt of l-chloropropanol-Z is prepared by slowly adding 46 parts of metallic sodium as an intimate dispersion in toluene to 191 parts of 1chloropropanol-Z in 350 parts of toluene while the temperature of the reactor is maintained at 020 C. In the same manner, the sodium alcoholate salt of 2-chloropropanol-1 is separately prepared from 23 parts of metallic sodium and 96 parts of 2-chloropropanol-l. To 168 parts of thiophosphoryl chloride is added a slurry of the above prepared alcoholate of 1-chloropropanol-2 in the super-- natent toluene at a; reaction temperature of 20 C. The time of addition is two hours. At the end of this period, the reaction mixture is cooled and sodium chloride removed by filtration. The residual product is then fractionated to yield di-(2-chloroisopropyl) -chlorothionophosphate. This material is then reacted with the alcoholate of 2-chloropropanol-l prepared above at 20 C. for an additional two hours. At the end or" this time, the reaction mixture is again cooled and sodium chloride removed by filtration. Toluene is then removed from the filtrate by distillation at 18 mm., and the product, di-(fi-chloroisopropyl)-(}3-chloro-n-propyl)-thionophosphate is further purified by fractionation under reduced pressure. The yield of desired product is nearly quantitative.

The superior lubricants or this invention can be pre- I pared readily by either of two general methods. The-first involves directly blending the desired amount of the appropriate'additive with the lubricating oil selected. An alternate method. involves preparing concentrated solutions of the additive in the lubricating oil, which concentrates can then be blended'with additional amounts of lubricating oil so as to prepare finished lubricants. Both of these methods are facilitated because of the high degree of solubility of the additives of this invention in lubricating oils. As a result, the amount of physical agitation required to assure homogeneity is-low.

The concentration of phosphorus-containing reagents employed in my finished lubricants is in general from about 0.05 to about 10 percent. It is preferable, however, to use such additives in concentrations from between about 0.1 to about 2 percent by weight.

With .such concentra-. tions, my finished oils are particularly efiective inreducing ti wild ping in a spark-fired internal combustion engine when used as crankcase lubricants. In the case of the preferred concentrated solutions, the high solubility of the phosphorus additives of this invention enables the formation of solutions containing as much as 25 percent by weight of the additive. Thus, the degree of concentration is largely within the discretion of the refiner.

The following examples wherein all parts and percentages are by weight further illustrate the methods of compounding the improved lubricant compositions of this invention.

Example VII To 950 parts of a phenol-treated, mixed-base mineral oil having a viscosity of 307 Saybolt Universal seconds (SUS) at 100 F. and 53.4 SUS at 210 F. and having a viscosity index (VI) of 103 was added 50 parts of tri- (fi-chloroisopropyl)-thionophosphate. The resulting mixture was stirred to assure homogeneity. The resulting lubricant contained approximately 5 percent of the additive and thus has a phosphorus content of about 0.45 percent.

Example VIII The procedure of Example VII is repeated using 10 parts of tri-(p-chloropropyl)-thionophosphate. The finished lubricant contains approximately one percent of the additive which is equivalent to a phosphorus content of about 0.1 percent.

Example IX To 980 parts of a solvent-extracted Pennsylvania bright stock having a Saybolt viscosity at 100 F. of 666 and at 210 F. of 76.0, a viscosity index of 107 and an aniline point of 116.0 C. is added 20 parts of tri-(B-brornoisopropyll-thionophosphate. After physical agitation, the finished lubricant contains about two percent of the additive.

Example X Five parts of tri-(B-chloropropyl)-trithiothionophosphate and 995 parts of a conventionally-refined Pennsylvania bright stock having a Saybolt viscosity at 100 F. of 570 SUS and at 210 1 of 68.0 SUS, a viscosity index of 100 and an aniline point of l10.5 C. are intimately mixed. The homogeneous finished oil contains approximately 0.5 percent of the additive.

Example XI Two parts of tri-(fi-iodoisopropyl)-thionophosphate is added to 998 parts of a solvent-extracted MidContinent bright stock having a Saybolt viscosity of 2049 SUS at 100 F. and 130.8 SUS at 210 F, a viscosity index of 98 and an aniline point of 125.2 C. The resulting mix ture blended by means of stirring contains approximately 0.2 percent of the additive.

Example XII To 950 parts of a solvent-extracted Coastal oil having a viscosity index of 54, an aniline point of 989 C., and a Sag/bolt viscosity at 100 F. of 948 SUS is added 25 parts of tri-(B-chloroisopropyl}-thionophosphate and 25 parts of tri-(fi -bron isopropyl)-thionophosphate. The resulting finishe oil contains approximately 5 percent of a corn posite ad vc of this invention.

Example XIII To 4500 parts of a phenol-treated, mixed-base mineral oil having a viscosity of 307 SUS at F. and having a viscosity index of 103 is added 500 parts of tri-(fl-bromoisopropyl)-thionophosphate and the mixture is stirred for three minutes. The resulting concentrated lubricant contains about 10 percent of the phosphorus additive.

Of the above illustrative examples numbers VII through XII inclusive exemplify direct methods of preparing the finished lubricants of this invention. Examples XIII and XIV typify methods for the formation of preformed concentrates which, as indicated, can then be diluted with additional base stock to prepare other finished lubricants of this invention. If desired, such concentrates can be used as transmission lubricants to partake of the extreme pressure properties possessed.

Improved lubricants of this invention are capable of markedly reducing the rate of wild ping which otherwise would occur with untreated lubricants. For example, a typical lubricant of this invention consisting essentially of a phenol-treated, mixed-base mineral oil having a viscosity of 307 SUS at 100 F. and tri-(dchloroisopropyD-thionophosphate, present in amount equal to five percent by weight, when used as crankcase lubricant in an engine operating on a commercial fuel containing three mililiters of tetraethyllead per gallon as a conventional antiknock fluid, produced but eight wild pings per hour of engine operation. In contrast, when the same engine was operated on the same fuel but with lubricant not treated according to this invention, it was found that the wild ping rate was about 94 percent greater. The unexpectedly great reduction in wild ping produced, while only illustrative of the effectiveness of my lubricants, was noteworthy in view of the low rate of oil consumption noted in the engine. Therefore, the effectiveness of the lubricants of this invention is obtainable irrespective of the condition or" the piston rings of the engine in which they are employed. Generally speaking, crankcase lubricants of this invention are capable of reducing the rate of wild ping by at least as much as 50 percent of base-line in gasoline engines.

While the advantages resulting from this invention have thus far been considered primarily from the standpoint of reduction in wild ping and other deposit problems, there are additional advantages. Among these is the enhanced stability of my improved lubricants. For example, the lubricants of this invention, including the preformed concentrates, are less susceptible to deterioration in the presence of oxygen, ozone, or other oxidation initiators, such as peroxides, even at operating engine crankcase temperatures. Thus, the amount of sludge, sediment and other undesirable decomposition products formed is at a minimum. Another advantage of this invention is reduction in engine corrosion, particularly of bearings and associated engine parts. Likewise, my lubricants possess improved film strength which is regarded as a function of oiliness or lubricity. In other words, my lubricants possess enhanced lubrication value over that obtainable from the identical untreated base stock.

The tri-(B-halopropyl)-thionophosphates as herein described can be used in a variety of motor oil stocks. Thus, lubricants to be improved may result from refining operations, such as dewaxing, acid treatment, solvent extraction, propane deasphalting, clay filtration or the like.

The lubricants of this invention can also contain other additives used to improve other properties of the oil. By way of example, my superior lubricants can contain detergent-dispersants, viscosity index improvers, antifoam agents, rusting inhibitors, dyes, or the like. The nature of such supplemental additives will be well known to those skilled in the art.

This is a continuation-in-part of my co-pending applications, Serial Nos. 392,456; 392,457; 392,458 and 392,459;

each filed November 16, 1953, all of which are now abandoned.

Having fully described the nature of the present invention, the need therefore, and the best mode devised for carrying it out, I do not intend to be limited except within the spirit and scope of the appended claims.

I claim:

1. An improvedv lubricating composition comprising mineral oil and from about 0.05 to about 25 percent by weight of a tri-(fi-halopropyl)-thionophosphate containing from 1 to 4 sulfur atoms per molecule, the halogen atoms of said thionophosphate each having an atomic weight of at least 35.

2. An improved lubricating composition comprising mineral lubricating oil having a viscosity corresponding to from-SAE 5W to SAE 50 inclusive, and, in amount sufficient to reduce the rate of wild ping in an internal combustion engine when said composition is employed as 10 a crankcase lubricant, a tri-(B-halopropyl)-thionophosphate containing one sulfur atom per molecule, the halogen atoms of said thionophosphate each having an atomic weight of at least 35, said amount being from about 0.05 to about 10 percent by weight.

3. The composition of claim 2 in which said thionophosphate is a tri-(fi chloropropyl)-thionophosphate.

4. A lubricant composition comprising a major proportion of mineral lubricating oil and from about 0.25% to about 5.0%, by weight, of tris-(Z-chloropropyl)-thionophosphate.

2,178,514 Prutton Oct. 31, 19-39 Smith Nov. 1, 1955 

1. AN IMPROVED LUBRICATING COMPOSITION COMPRISING MINERAL OIL AND FROM ABOUT 0.05 TO ABOUT 25 PERCENT BY WEIGHT OF A TRI-(B-HALOPROPLY)-THIONOPHOSPHATE CONTAINING FROM 1 TO 4 SULFUR ATOMS PER MOLECULE, THE HALOGEN ATOMS OF SAID THIONOPHOSPHATE EACH HAVING AN ATOMIC WEIGHT OF AT LEAST
 35. 